Structural ceramics incorporating whiskers, platelets, and particulate phases

Conference · Wed Feb 01 04:00:00 EST 1995

OSTI ID:10120131

Becher, P F; Hsueh, C H; Alexander, K B; Lin, H T; Warwick, W H; Westmoreland, C G; Waters, S B

Advances in the development of ceramics toughened with whiskers, particles or platelets are reviewed with emphasis on the development of both fracture strength and toughness. In the systems described here, the primary focus is on toughening attained by crack bridging processes (e.g., frictional bridging and pullout) in the wake of the crack tip. Examples of the influence of resultant improvements in other mechanical properties (e.g., strength, fatigue, and thermal shock resistance) are also given for whisker-reinforced aluminas. It is shown that similar increases in fracture toughness may also be brought about by the incorporation of platelet phases in ceramics, either by their addition or by their formation during densification. In addition, the development of ceramic matrix composites containing transformable tetragonal zirconia grains is discussed. Here, it is shown that both the zirconia grain size and content, combined with thermal expansion mismatch stresses, influence the transformability of the zirconia and the resultant transformation toughening effects. Examples reveal that by addressing the microstructural characteristics, as well as the reinforcement and matrix properties, high strength toughened ceramics with exceptional damage resistance can be developed.

• Research Organization: Oak Ridge National Lab., TN (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 10120131
• Report Number(s): CONF-941059--2; ON: DE95007048
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202
360203
ALUMINIUM OXIDES
CERAMICS
FRACTURE PROPERTIES
GRAIN SIZE
HOT PRESSING
MECHANICAL PROPERTIES
MICROSTRUCTURE
QUENCHING
REINFORCED MATERIALS
SILICON CARBIDES
SILICON NITRIDES
SINTERING
STRUCTURE AND PHASE STUDIES
THERMAL EXPANSION
THERMAL SHOCK
WHISKERS
ZIRCONIUM OXIDES